PITTSBURGH—Less than a minute into Sunday night’s game, Byron Leftwich did his best impersonation of Cam Newton, Steve Young or Michael Vick.

Never known for his speed, Leftwich rolled to his right, found daylight, and started lumbering downfield. Somehow, he split two Ravens’ defenders and kept chugging toward the end zone as the crowd at Heinz Field roared at the improbable sight. When it was over, Leftwich had scrambled 31 yards for a touchdown to give the Steelers a 7-0 lead.

Leftwich’s teammates mobbed him. The Ravens looked at each other is disbelief.

To put Leftwich’s 31-yard scramble in perspective, he had not run for 31 yards in an entire season since 2006. But making his first start this season in place of the injured Ben Roethlisberger, Leftwich was perhaps feeling an extra rush of adrenaline. His unlikely run gave the Steelers an early shot in the arm. And it gave Leftwich a career moment to remember.